Methods and systems for a multi-speed electric axle assembly

ABSTRACT

Various methods and systems are provided for a multi-speed electric axle assembly with three gear ratios. The multi-speed electric axle assembly includes one or more power supplies, one or more shafts operatively coupled to the one or more power supplies and a differential, and one or more Ravigneaux gear assemblies integrated with the one or more shafts. The one or more Ravigneaux gear assemblies of the multi-speed electric axle assembly providing the three gear ratios.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication No. 62/831,784, entitled “Multi-Speed Electric AxleAssembly”, and filed on Apr. 10, 2019. The entire contents of theabove-listed application are incorporated herein by reference for allpurposes.

FIELD

Embodiments of the subject matter disclosed herein relate to amulti-speed electric vehicle axle assembly.

BACKGROUND

Axle assemblies for electric vehicles may include a single-speedtransmission as electric motors have a wider rpm window in which themotor can operate efficiently as compared to internal combustionengines. However, the use of single-speed transmissions in electricvehicles demands compromise between low-end acceleration and increasedspeeds with most manufacturers favoring acceleration over higher speeds.

BRIEF DESCRIPTION

Further, even in multi-speed electric vehicle transmissions, the desirefor minimum weight and a compact package can limit the speed ratiosavailable. As such, in one embodiment, a system includes a multi-speedelectric axle assembly with three gear ratios. The multi-speed electricaxle assembly includes one or more power supplies, one or more shaftsoperatively coupled to the one or more power supplies and adifferential, and one or more Ravigneaux gear assemblies integrated withthe one or more shafts. The one or more Ravigneaux gear assemblies ofthe multi-speed electric axle assembly provide the three gear ratios.

It should be understood that the brief description above is provided tointroduce in simplified form a selection of concepts that are furtherdescribed in the detailed description. It is not meant to identify keyor essential features of the claimed subject matter, the scope of whichis defined uniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will be better understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 is a schematic view of a first embodiment of a multi-speedelectric axle assembly in accordance with the present disclosure;

FIG. 2 is a schematic view of a second embodiment of a multi-speedelectric axle assembly in accordance with the present disclosure;

FIG. 3 is a schematic view of a third embodiment of a multi-speedelectric axle assembly in accordance with the present disclosure;

FIG. 4 is a schematic view of a fourth embodiment of a multi-speedelectric axle assembly in accordance with the present disclosure; and

FIG. 5 is a schematic view of a fifth embodiment of a multi-speedelectric axle assembly in accordance with the present disclosure.

DETAILED DESCRIPTION

Electric vehicles (EVs) may employ a single gear to drive the wheels aselectric motors have a wider RPM window in which the motor can operateefficiently as compared to conventional internal combustion engines,with the motors being power efficient throughout the entire range of theRPM window. As such, EVs do not demand a specific RPM range to be usedduring low-speed driving or under acceleration and may produce almostinstantaneous torque from zero revs. Thus, a gear ratio for an electricvehicle axle assembly that contains a balance between acceleration andtop speed is selected. If the gear ratio is too low, the EV mayaccelerate very quickly but be limited to a low top speed.Alternatively, if the gear ratio is high, the gearing may be optimal fortop speeds but acceleration will be limited. As such, there is a demandfor EVs that may achieve increased speeds without comprisingacceleration. Further, different customer applications (e.g., racingapplications) may demand or benefit from an electric axle assemblyhaving multiple gear ratios.

Thus, according to the embodiments disclosed herein, a multi-speedelectric axle assembly that permits an EV to have three individual gearratios is provided. The multi-speed electric axle assembly comprises oneor more power supplies and a set of shafts integrated with a gearassembly, with exactly three individual gear ratios achieved by lockingdifferent portions of the gear assembly. The individual gear ratios maybe selected via various clutch actuations using a set of actuators andclutches. By employing the multi-speed electric axle assembly, EVs mayhave better launch performance using lower gears, more efficienthigh-speed driving using higher gears, and achieve increased speedswithout limiting acceleration. Further, as a single manual transmissionstyle shift synchronizer may be used for all three gears, the cost,weight, and complexity of the gearbox may be reduced. Additionally, byadvantageously utilizing the three gears, mid-speed performance may beincreased as well as overall vehicle efficiency as the motor anddriveline may be maintained in a peak efficiency zone. In some examples,the gear assembly may be a Ravigneaux or Ravigneaux-type gear set. TheRavigneaux or Ravigneaux-type gear set may be advantageous when threegear ratios are demanded as the gear set provides a compact solution ascompared to other gear architectures. All three gear ratios may beachieved by selectively grounding a component (e.g., a planetary gearcarrier, a large sun gear) of the Ravigneaux or Ravigneaux-type gearset, with the third gear creating a 1:1 final ratio. Utilizing a 1:1final ratio may also increase vehicle efficiency by means of frictionreduction which, in turn, leads to an increased driving range for thevehicle.

Embodiments of a multi-speed electric axle assembly are illustrated inFIGS. 1-5. Each embodiment may be utilized as an electric drive axle.Each embodiment may have applications in commercial vehicles, both lightduty and heavy duty vehicles, and for passenger, off-highway, and sportutility vehicles. Additionally, each embodiment of the multi-speedelectric axle assembly may be adapted for use in front and/or reardriving axles, as well as steerable and non-steerable axles. Themulti-speed electric axle assemblies described herein may also haveindustrial, locomotive, military, agricultural, and aerospaceapplications.

A first embodiment of the multi-speed electric axle assembly 10 in avehicle 1 is shown in FIG. 1. The axle assembly 10 includes a firstelectric motor generator 12, a second electric motor generator 16, and afirst shaft 14. The first electric motor generator 12 and the secondelectric motor generator 16 each provide power which can drive the axleassembly 10. The first shaft 14 is operably coupled to the firstelectric motor generator 12 for rotation. In some examples, the firstshaft 14 may also be operably coupled to the second electric motorgenerator 16 for rotation. In some examples, the first shaft 14 may besupported for rotation by one or more bearings. The first shaft 14extends from the first and second electric motor generators 12, 16 intoa first gear assembly 18. Power communicated to the first gear assembly18 from the first and second electric motor generators 12, 16 istransmitted by the first shaft 14 into only one side 20 of the firstgear assembly 18.

The first gear assembly 18 comprises a first sun gear 22. The first sungear 22 is operably coupled to the first shaft 14 and rotates therewith.The first sun gear 22 is in meshed engagement with a first planetarygear set 24. The first planetary gear set 24 is in meshed engagementwith a second planetary gear set 26. The second planetary gear set 26 isin meshed engagement with the first planetary gear set 24, a second sungear 28, and a ring gear 30. The first sun gear 22 has an outermostdiameter that is smaller than an outermost diameter of the second sungear 28. The first planetary gear set 24 and the second planetary gearset 26 are coupled to a planet carrier 52. The first planetary gear set24 and the second planetary gear set 26 rotate independently of theplanet carrier. The first planetary gear set 24 and the second planetarygear 26 set co-rotate with a fixed gear ratio with respect to eachother. In some embodiments, the first gear assembly 18 may be aRavigneaux gear set.

In some embodiments, rotation locking assemblies may be selectivelyengageable with different portions of the first gear assembly 18 therebypermitting the vehicle 1 to operate at three different gear ratios. Forexample, the rotation locking assemblies may be clutches and actuatorscommunicatively coupled to a controller 54. In response to user input,the controller 54 may send a signal causing one or more of the clutchesto selectively engage a portion of the first gear assembly 18. A firstclutch 56 may be selectively engageable with at least a portion of theplanet carrier 52. When the first clutch 56 is engaged with the planetcarrier 52, the planet carrier 52 is held stationary and does notrotate. A second clutch 58 may be selectively engageable with at least aportion of the second sun gear 28. When the second clutch 58 is engagedwith the second sun gear 28, the second sun gear 28 is held stationaryand does not rotate. A third clutch 60 may be selectively engageablewith at least a portion of the first sun gear 22 and the second sun gear28. When the third clutch 60 is engaged with the first sun gear 22 andthe second sun gear 28, the first sun gear 22 and the second sun gear 28are held and rotate together.

The ring gear 30 is fixedly coupled to a second gear assembly 32. Thesecond gear assembly 32 comprises a first gear 34. The first gear 34 isin meshing engagement with a second gear 36. The second gear 36 isoperably coupled with a second shaft 38. The second shaft 38 may besupported for rotation with one or more bearings. In some embodiments,the second shaft 38 is provided in a parallel relationship with thefirst shaft 14. A third gear 40 may be disposed at an end of the secondshaft 38. The third gear 40 may be of the pinion variety and is inmeshing engagement with a ring gear 42 disposed on a differential 44.The differential 44 may be operatively attached to an axle 46. The axle46 may comprise a first axle shaft 48 and a second axle shaft 50. Thefirst axle shaft 48 may be operatively coupled to a first wheel 62 andthe second axle shaft 50 may be operatively coupled to a second wheel64.

Thus, the vehicle may operate at a first gear ratio, a second gearratio, and a third gear ratio. A first gear ratio may be output when theplanet carrier 52 is held stationary and does not rotate. A second gearratio may be output when the second sun gear 28 is held stationary anddoes not rotate. A third gear ratio may be output when the first sungear 22 and the second sun gear 28 are held and rotate together. Thefirst, second and third gear ratios may be specified as 3.850:1, 1.974:1and 1:1, respectively. This particular ratio selection and overall ratiospread may provide sufficient ratio overlap for the rpm range of themotor generators 12, 16. In some examples, the first, second, and thirdgear ratios may not be specified as 3.850:1, 1.974:1 and 1:1,respectively. As illustrated in FIG. 1, the multi-speed axle assembly 10may be in a perpendicular configuration. As used herein the phrase“perpendicular configuration” refers to the electric motor generator(s)providing power that is transmitted perpendicular to the orientation ofthe axle driving wheel rotation (e.g., axle 46).

However, as illustrated by a second non-limiting embodiment in FIG. 2, amulti-speed electric axle assembly 100 of the vehicle 1 may be in aparallel configuration. As used herein, the phrase “parallelconfiguration” refers to the electric motor generator(s) providing powerthat is transmitted parallel to the orientation of the axle drivingwheel rotation. The axle assembly 100 comprises a differential 102operatively attached to a first axle shaft 104 that extends through afirst hollow shaft 106 and a second axle shaft 108 that extends througha second hollow shaft 110. An axis of rotation of the first axle shaft104 may be aligned with an axis of rotation of the first hollow shaft106. Similarly, an axis of rotation of the second axle shaft 108 may bealigned with an axis of rotation of the second hollow shaft 110.Additionally, the first hollow shaft 106 and the second hollow shaft 110may be longitudinally aligned. The first axle shaft 104 may beoperatively coupled to a first wheel 138 and the second axle shaft 108may be operatively coupled to a second wheel 140.

The first hollow shaft 106 extends perpendicularly from and isoperatively coupled to a first electric motor generator 112. The secondhollow shaft 110 extends perpendicularly from and is operatively coupledto a second electric motor generator 114. Coupling the first hollowshaft 106 to the first electric motor generator 112 enables the firsthollow shaft 106 to rotate about its axis of rotation. Coupling thesecond hollow shaft 110 to the second electric motor generator 114enables the second hollow shaft 110 to rotate about its axis ofrotation. The first hollow shaft 106 and the second hollow shaft 110 maybe supported for rotation by one or more bearings.

The first hollow shaft 106 may be operatively connected to a first geartrain 116. The first gear train 116 may be used to provide input to andoutput from the first electric motor generator 112 via the first hollowshaft 106. The second hollow shaft 110 may be operatively connected to asecond gear train 118. The second gear train 118 may be used to provideinput to and output from the second electric motor generator 114 via thesecond hollow shaft 110. The first gear train 116 and the second geartrain 118 are similarly configured and thus, for brevity, only the firstgear train 116 will be described below.

The first gear train 116 comprises a first gear 120 operatively attachedto and rotating with the first hollow shaft 106. The first gear 120 anda second gear 122 are engaged and rotate together. The second gear 122is operatively attached to and rotates with a first shaft 124. The firstshaft 124 extends toward the second gear train 118 and is operativelyattached to a second gear 126 of the second gear train 118, whichrotates with the first shaft 124. The first shaft 124 may be supportedfor rotation by one or more bearings. In some embodiments, the firstshaft 124 is provided in a parallel relationship with the first hollowshaft 106 and the second hollow shaft 110. The first shaft 124 extendsinto and through a first gear assembly 128 and a second gear assembly130.

The first shaft 124 communicates power provided by the first electricmotor generator 112 and the second electric motor generator 114 to thefirst gear assembly 128. The power communicated to the first gearassembly 128 from the first and second electric motor generators 112,114 is transmitted by the first shaft 124 into both sides of the firstgear assembly 128. In some examples, the first gear assembly 128 may beconfigured like the embodiment of the first gear assembly 18 of themulti-speed electric axle assembly 10 illustrated in FIG. 1. In thesecond embodiment, a ring gear 132 of the first gear assembly 128 isfixedly coupled to the second gear assembly 130. More particularly, thering gear 132 is coupled with a first gear 134 of the second gearassembly 130. The first gear 134 is in meshing engagement with a secondgear 136. In some embodiments, the first gear 134 and the second gear136 may each be spur gears. For example, the first gear 134 may be apinion gear and the second gear 136 may be a bull gear. The second gear136 may be disposed on the differential 102. The differential 102 may beconfigured and operate like the differential 44 of the first embodimentof the multi-speed electric axle assembly 10 illustrated in FIG. 1.

Thus, the vehicle may operate at a first gear ratio, a second gearratio, and a third gear ratio. For example, clutches communicativelycoupled to the controller 54 may selectively engage different portionsof the first gear assembly 128 in response to user input. For example, afirst clutch 142 may selectively engage during the initial launch of thevehicle from an initial stopped position. The first clutch 142 may alsoengage if the vehicle is already in the second gear ratio and has sloweddown to a speed where the first or the second electric motor generator112, 114 cannot generate enough force to accelerate the vehicle at therate as requested by the driver. A second clutch 144 may selectivelyengage during moderate speed driving and low speed driving if thevehicle load and requested acceleration rate as requested by the driverare both relatively low. The second clutch 144 may also engage if thevehicle is already in the third gear ratio and has slowed down to aspeed where the first or the second electric motor generator 112, 114cannot generate enough force to accelerate the vehicle at the rate asrequested by the driver. A third clutch 146 may selectively engageduring high speed driving or moderate speed driving if the vehicle loadand requested acceleration rate as requested by the driver are bothrelatively low.

In a third embodiment, as illustrated in FIG. 3, a multi-speed electricaxle assembly 200 of the vehicle 1 may be in a parallel configurationand power communicated to a first gear assembly from only one side ofthe first gear assembly. For example, the axle assembly 200 may comprisea differential 202 operatively attached to an axle 204. The axle 204 maycomprise a first axle shaft 206 and a second axle shaft 208. The firstaxle shaft 206 extends through a hollow shaft 210. An axis of rotationof the first axle shaft 206 may be aligned with an axis of rotation ofthe hollow shaft 210. The first axle shaft 206 may be operativelycoupled to a first wheel 234 and the second axle shaft 208 may beoperatively coupled to a second wheel 236. The hollow shaft 210perpendicularly extends from and is operatively coupled to a firstelectric motor generator 212. Coupling the hollow shaft 210 to the firstelectric motor generator 212 enables the hollow shaft 210 to rotateabout its axis of rotation. The hollow shaft 210 may be supported forrotation by one or more bearings.

The hollow shaft 210 may be operatively connected to a first gear train214. The first gear train 214 may be utilized to provide input to andoutput from the first electric motor generator 212. The first gear train214 comprises a first gear 216 and a second gear 218. The first gear 216is operatively attached to and rotating with the hollow shaft 210. Thefirst gear 216 and the second gear 218 are engaged and rotate together.The second gear 218 is operatively attached to and rotates with a firstshaft 220.

The first shaft 220 longitudinally extends toward and is operativelycoupled to a second electric motor generator 222. The first shaft 220rotates about an axis of rotation from power transmitted by the secondelectric motor generator 222 and the first electric motor generator 212,with power from transmitted from the first electric motor generator 212by way of the first gear train 214 and the hollow shaft 210. The firstshaft 220 may be supported for rotation by one or more bearings. In someembodiments, the first shaft 220 is provided in a parallel relationshipwith the hollow shaft 210. The first shaft 220 also extends toward,into, and through a first gear assembly 224 and a second gear assembly226.

The first shaft 220 communicates power provided by the first and secondelectric motor generators 212, 222 to the first gear assembly 224. Asillustrated in FIG. 3, the power communicated to the first gear assembly224 from the first and second electric motor generators 212, 222 istransmitted by the first shaft 220 into only one side of the first gearassembly 224. In some examples, the first gear assembly 224 may beconfigured like the first gear assembly 18 of the first embodiment ofthe multi-speed electric axle assembly 10 illustrated in FIG. 1.

In the third embodiment, a ring gear 228 of the first gear assembly 224is fixedly coupled to the second gear assembly 226. More particularly,the ring gear 228 is coupled with a first gear 230 of the second gearassembly 226. The first gear 230 is in meshing engagement with a secondgear 232. In some embodiments, the first gear 230 and the second gear232 may each be spur gears. For example, the first gear 230 may be apinion gear and the second gear 232 may be a bull gear. The second gear232 may be disposed on the differential 202. The differential 202 may beconfigured and operate like the differential 44 of the first embodimentof the multi-speed electric axle assembly 10 illustrated in FIG. 1.

Thus, the vehicle may operate at a first gear ratio, a second gearratio, and a third gear ratio. For example, clutches communicativelycoupled to the controller 54 may selectively engage different portionsof the first gear assembly 224 in response to user input. For example, afirst clutch 238 may selectively engage during the initial launch of thevehicle from an initial stopped position. The first clutch 238 may alsoengage if the vehicle is already in the second gear ratio and has sloweddown to a speed where the first or second electric motor generators 212,222 cannot generate enough force to accelerate the vehicle at the rateas requested by the driver. A second clutch 240 may selectively engageduring moderate speed driving and low speed driving if the vehicle loadand requested acceleration rate as requested by the driver are bothrelatively low. The second clutch 240 may also engage if the vehicle isalready in the third gear ratio and has slowed down to a speed where thefirst or second electric motor generators 212, 222 cannot generateenough force to accelerate the vehicle at the rate as requested by thedriver. A third clutch 242 may selectively engage during high speeddriving or moderate speed driving if the vehicle load and requestedacceleration rate as requested by the driver are both relatively low.

In a fourth embodiment, as illustrated in FIG. 4, a multi-speed electricaxle assembly 300 of the vehicle 1 may be in a parallel configurationand power communicated to a first gear assembly from both sides of afirst gear assembly. The axle assembly 300 comprises a differential 302operatively attached to an axle 304. The axle 304 may comprise a firstaxle shaft 306 and a second axle shaft 308. The second axle shaft 308extends through a hollow shaft 310. The first axle shaft 306 may beoperatively coupled to a first wheel 334 and the second axle shaft 308may be operatively coupled to a second wheel 336. An axis of rotation ofthe second axle shaft 308 may be aligned with an axis of rotation of thehollow shaft 310.

The hollow shaft 310 extends perpendicularly from and is operativelycoupled to a first electric motor generator 312. Coupling the hollowshaft 310 to the first electric motor generator 312 enables the hollowshaft 310 to rotate about its axis of rotation. The hollow shaft 310 maybe supported for rotation by one or more bearings. The hollow shaft 310may be operatively connected to a first gear train 314. The first geartrain 314 may be used to provide input to and output from the firstelectric motor generator 312. The first gear train 314 comprises a firstgear 316 operatively attached to and rotating with the hollow shaft 310.The first gear 316 and a second gear 318 are engaged and rotatetogether. The second gear 318 is operatively attached to and rotateswith a first shaft 320.

The first shaft 320 extends toward and is operatively coupled to asecond electric motor generator 322. The first shaft 320 rotates aboutan axis of rotation from power transmitted by the second electric motorgenerator 322 and the first electric motor generator 312, with powertransmitted from the first electric motor generator 312 by way of thefirst gear train 314 and the hollow shaft 310. The first shaft 320 maybe supported for rotation by one or more bearings. In some embodiments,the first shaft 320 is provided in a parallel relationship with thehollow shaft 310.

The first shaft 320 also extends away from the first gear train 314toward, into, and through a first gear assembly 324 and a second gearassembly 326. The first shaft 320 communicates power provided by thefirst and second electric motor generators 312, 322 to the first gearassembly 324. The power communicated to the first gear assembly 324 fromthe first electric motor generator 312 is transmitted by the first shaft320 into a first side of the first gear assembly 324 and the powercommunicated to the first gear assembly 324 from the second electricmotor generator 322 is transmitted by the first shaft 320 into a secondside of the first gear assembly 324. In some embodiments, the first gearassembly 324 is configured like the first gear assembly 18 of the firstembodiment of the multi-speed electric axle assembly 10 illustrated inFIG. 1.

In the fourth embodiment, a ring gear 328 of the first gear assembly 324is fixedly coupled to the second gear assembly 326. More particularly,the ring gear 328 is coupled with a first gear 330 of the second gearassembly 326. The first gear 330 is in meshing engagement with a secondgear 332. In some embodiments, the first gear 330 and the second gear332 may each be spur gears. For example, the first gear 330 may be apinion gear and the second gear 332 may be a bull gear. The second gear332 may be disposed on the differential 302. The differential 302 may beconfigured and operate like the differential 44 of the first embodimentof the multi-speed electric axle assembly 10 illustrated in FIG. 1.

Thus, the vehicle may operate at a first gear ratio, a second gearratio, and a third gear ratio. For example, clutches communicativelycoupled to the controller 54 may selectively engage different portionsof the first gear assembly 324 in response to user input. For example, afirst clutch 338 may selectively engage during the initial launch of thevehicle from an initial stopped position. The first clutch 338 may alsoengage if the vehicle is already in the second gear ratio and has sloweddown to a speed where the first or second electric motor generators 312,322 cannot generate enough force to accelerate the vehicle at the rateas requested by the driver. A second clutch 340 may selectively engageduring moderate speed driving and low speed driving if the vehicle loadand requested acceleration rate as requested by the driver are bothrelatively low. The second clutch 340 may also engage if the vehicle isalready in the third gear ratio and has slowed down to a speed where thefirst and second electric motor generators 312, 322 cannot generateenough force to accelerate the vehicle at the rate as requested by thedriver. A third clutch 342 may selectively engage during high speeddriving or moderate speed driving if the vehicle load and requestedacceleration rate as requested by the driver are both relatively low.

A fifth embodiment of a multi-speed electric axle assembly 400 of thevehicle 1 is illustrated in FIG. 5. In the fifth embodiment, themulti-speed electric axle assembly 400 comprises a first electric motorgenerator 402, with a first shaft 404 operably coupled to the firstelectric motor generator 402 for rotation. The first shaft 404 extendsfrom the first electric motor generator 402 toward a second electricmotor generator 406, with the first shaft 404 also operably coupled tothe second electric motor generator 406 for rotation. The first electricmotor generator 402 and the second electric motor generator 406 eachprovide power, which can drive the axle assembly 400. The first shaft404 may be supported for rotation by one or more bearings.

The first shaft 404 is hollow and also extends into a first gearassembly 408. Power may be communicated to the first gear assembly 408from the first and second electric motor generators 402, 406 via thefirst shaft 404, with power transmitted into only one side of the firstgear assembly 408. In some examples, the first gear assembly 408 may beconfigured like the first gear assembly 18 of the first embodiment ofthe multi-speed electric axle assembly 10 illustrated in FIG. 1. In thefifth embodiment, a ring gear 410 of the first gear assembly 408 isoperably coupled to a differential 412. More particularly, the ring gear410 is operably coupled to a first gear set 414 and a second gear set416 of the differential 412. Each gear of the first gear set 414 is inmeshing engagement with a gear of the second gear set 416. In someembodiments, the first gear set 414 and the second gear set 416 may eachcomprise planetary gears. For example, each gear of the first gear set414 is in meshing engagement with a sun gear 418. Each gear of thesecond gear set 416 is in meshing engagement with a ring gear 420. Dueto the configuration of the axle assembly 400, the differential 412 mayoperate at a first speed, a second speed, and a third speed as furtherdescribed below.

The differential 412 may be operatively attached to an axle 421. Theaxle 421 may comprise a first axle shaft 422 and a second axle shaft424. The first axle shaft 422 may be operatively coupled to a firstwheel 438 and the second axle shaft 424 may be operatively coupled to asecond wheel 440. The sun gear 418 is attached to the first axle shaft422. The ring gear 420 is operably coupled to the second axle shaft 424.In some embodiments, the ring gear 420 is coupled to the second axleshaft 424 via a splined connection. In some embodiments, thedifferential 412 is of the epicyclic variety. The first axle shaft 422may be supported for rotation with one or more bearings (not depicted).The first axle shaft 422 extends away from the sun gear 418 toward andthrough the first gear assembly 408. The first axle shaft 422 alsoextends toward and through the hollow first shaft 404, terminating at afirst gear reduction 426 located beyond the first and second electricmotor generators 402, 406.

The first gear reduction 426 is operably coupled to an end of the firstaxle shaft 422 (e.g., opposite the end of the first axle shaft 422attached to the sun gear 418). In an embodiment, the first gearreduction 426 includes a sun gear 428. The sun gear 428 is in meshingengagement with a planetary gear set 430. In some embodiments, theplanetary gear set 430 is in meshing engagement with a stationary ring432. Preferably, the planetary gear set 430 is held by a planet carrier434. The planet carrier 434 is coupled with a wheel for rotationtherewith.

From the differential 412, the second axle shaft 424 extends toward anend of the second axle shaft 424. The second axle shaft 424 may besupported for rotation with one or more bearings. A second gearreduction 426 is operably coupled to the end of the second axle shaft424. The second gear reduction 436 is configured in a manner similar tothe first gear reduction 426 and thus includes a planetary gear set heldby a planetary carrier, where the planetary gear set is in meshingengagement with a stationary ring.

Thus, the multi-speed electric axle assembly 400 may operate at a firstgear ratio, a second gear ratio, and a third gear ratio. For example,clutches communicatively coupled to the controller 54 may selectivelyengage different portions of the first gear assembly 408 in response touser input. For example, a first clutch 442 may selectively engageduring the initial launch of the vehicle from an initial stoppedposition. The first clutch 442 may also engage if the vehicle is alreadyin the second gear ratio and has slowed down to a speed where the firstor second electric motor generators 402, 406 cannot generate enoughforce to accelerate the vehicle at the rate as requested by the driver.A second clutch 444 may selectively engage during moderate speed drivingand low speed driving if the vehicle load and requested accelerationrate as requested by the driver are both relatively low. The secondclutch 444 may also engage if the vehicle is already in the third gearratio and has slowed down to a speed where the first or second electricmotor generators 402, 406 cannot generate enough force to accelerate thevehicle at the rate as requested by the driver. A third clutch 446 mayselectively engage during high speed driving or moderate speed drivingif the vehicle load and requested acceleration rate as requested by thedriver are both relatively low.

The foregoing description is considered as illustrative only of theprinciples of the invention. Further, since numerous modifications andchanges will readily occur to those skilled in the art, it is notdesired to limit the invention to the exact construction and processesshown and described herein. Accordingly, all suitable modifications andequivalents may be considered as falling within the scope of theinvention as defined by the claims, which follow below.

FIGS. 1-5 show example configurations with relative positioning of thevarious components. If shown directly contacting each other, or directlycoupled, then such elements may be referred to as directly contacting ordirectly coupled, respectively, at least in one example. Similarly,elements shown contiguous or adjacent to one another may be contiguousor adjacent to each other, respectively, at least in one example. As anexample, components laying in face-sharing contact with each other maybe referred to as in face-sharing contact. As another example, elementspositioned apart from each other with only a space there-between and noother components may be referred to as such, in at least one example. Asyet another example, elements shown above/below one another, at oppositesides to one another, or to the left/right of one another may bereferred to as such, relative to one another. Further, as shown in thefigures, a topmost element or point of element may be referred to as a“top” of the component and a bottommost element or point of the elementmay be referred to as a “bottom” of the component, in at least oneexample. As used herein, top/bottom, upper/lower, above/below, may berelative to a vertical axis of the figures and used to describepositioning of elements of the figures relative to one another. As such,elements shown above other elements are positioned vertically above theother elements, in one example. As yet another example, shapes of theelements depicted within the figures may be referred to as having thoseshapes (e.g., such as being circular, straight, planar, curved, rounded,chamfered, angled, or the like). Further, elements shown intersectingone another may be referred to as intersecting elements or intersectingone another, in at least one example. Further still, an element shownwithin another element or shown outside of another element may bereferred as such, in one example.

In this way, a multi-speed electric axle assembly according to theembodiments disclosed herein may provide a user with exactly threeindividual gear ratios to select from when driving an EV. Themulti-speed electric axle assembly comprises one or more power suppliesand one or more shafts integrated with a gear assembly, with the threeindividual gear ratios achieved by locking different portions of thegear assembly. The individual gear ratios may be selected via variousclutch actuations using a set of actuators and clutches. By utilizing asimple clutch assembly as described herein, the multi-speed electricaxle assembly may take up minimal space within a vehicle whilemaintaining a high torque carrying capacity.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising,”“including,” or “having” an element or a plurality of elements having aparticular property may include additional such elements not having thatproperty. The terms “including” and “in which” are used as theplain-language equivalents of the respective terms “comprising” and“wherein.” Moreover, the terms “first,” “second,” and “third,” etc. areused merely as labels, and are not intended to impose numericalrequirements or a particular positional order on their objects.

This written description uses examples to disclose the invention,including the best mode, and also to enable a person of ordinary skillin the relevant art to practice the invention, including making andusing any devices or systems and performing any incorporated methods.The patentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those of ordinary skill in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

1. A multi-speed electric axle assembly with three gear ratioscomprising: one or more power supplies; one or more shafts operativelycoupled to the one or more power supplies and a differential; and one ormore Ravigneaux gear assemblies integrated with the one or more shafts,the one or more Ravigneaux gear assemblies providing the three gearratios.
 2. The multi-speed electric axle assembly of claim 1, whereindifferent portions of the one or more Ravigneaux gear assemblies arelocked to achieve the three gear ratios.
 3. The multi-speed electricaxle assembly of claim 1, wherein the one or more power suppliestransmit power parallel to the orientation of an axle driving wheelrotation.
 4. The multi-speed electric axle assembly of claim 1, whereinthe one or more power supplies transmit power perpendicular to theorientation of an axle driving wheel rotation.
 5. The multi-speedelectric axle assembly of claim 1, wherein power is transmitted from theone or more power supplies to only one side of a first Ravigneaux gearassembly of the one or more Ravigneaux gear assemblies via the one ormore shafts.
 6. The multi-speed electric axle assembly of claim 1,wherein power is transmitted from the one or more power supplies intoboth sides of a first Ravigneaux gear assembly of the one or moreRavigneaux gear assemblies via the one or more shafts.
 7. Themulti-speed electric axle assembly of claim 1, wherein the three gearratios are selected via different clutch actuations using a set ofactuators and clutches.
 8. The multi-speed electric axle assembly ofclaim 1, wherein one or more rotation locking assemblies are selectivelyengageable with at least three different portions of the one or moreRavigneaux gear assemblies.
 9. The multi-speed electric axle assembly ofclaim 8, wherein selectively engaging the at least three differentportions of the one or more Ravigneaux gear assemblies permits themulti-speed electric axle assembly to operate at the three gear ratios.10. A multi-speed electric axle assembly for a vehicle comprising: afirst electric motor generator; a first shaft operably coupled to thefirst electric motor for rotation; a first gear assembly in mechanicalcommunication with the first shaft, the first gear assembly comprising:a first sun gear operably coupled to the first shaft; a first planetarygear set in meshed engagement with the first sun gear; and a secondplanetary gear set in meshed engagement with the first planetary gearset and a second sun gear, where the second planetary gear set and thefirst planetary gear set are both coupled to and rotate independently ofa planet carrier; a differential in mechanical communication with thefirst gear assembly; and an axle shaft operatively attached to thedifferential, wherein the multi-speed electric axle assembly operates atthree different gear ratios.
 11. The multi-speed electric axle assemblyof claim 10, wherein the second planetary gear set and the firstplanetary gear set co-rotate with a fixed gear ratio with respect toeach other.
 12. The multi-speed electric axle assembly of claim 11,wherein the vehicle operates at a first gear ratio when the planetcarrier is held in a stationary position.
 13. The multi-speed electricaxle assembly of claim 12, wherein the vehicle operates at a second gearratio when the second sun gear is held in a stationary position.
 14. Themulti-speed electric axle assembly of claim 13, wherein the vehicleoperates at a third gear ratio when the first sun gear and the secondsun gear rotate together.
 15. The multi-speed electric axle assembly ofclaim 10, wherein a first clutch is selectively engageable with at leasta portion of the planet carrier.
 16. The multi-speed electric axleassembly of claim 15, wherein a second clutch is selectively engageablewith at least a portion of the second sun gear.
 17. The multi-speedelectric axle assembly of claim 16, wherein a third clutch isselectively engageable with at least a portion of the first sun gear andthe second sun gear.
 18. The multi-speed electric axle assembly of claim10, wherein the first gear assembly is a Ravigneaux gear assembly. 19.The multi-speed electric axle assembly of claim 10, wherein the firstshaft is rotatably supported by one or more bearings.
 20. A multi-speedelectric axle assembly, comprising: a first motor generator; a firstshaft in mechanical communication with the first motor generator; afirst gear assembly in mechanical communication the first shaft, thefirst gear assembly including a first sun gear, a first planetary gearset in meshing engagement with the first sun gear, a second planetarygear set in meshing engagement with the first planetary gear set, asecond sun gear, and a ring gear, wherein the first planetary gear setand the second planetary gear set are coupled to a carrier; wherein thecarrier is selectively coupled to a first grounded member to operate ina first mode; wherein the second sun gear is selectively coupled to asecond grounded member to operate in a second mode; and wherein thefirst sun gear is selectively coupled to the second sun gear to operatein a third mode; and a differential in mechanical communication with thefirst gear assembly.